JPS62193635A - Turbine type stirrer assembly - Google Patents

Abstract

Turbine agitator assembly for the dispersion of a fluid in a liquid comprises (a) a reservoir for liquid; (b) a rotor mounted in the reservoir with a number of radially extending blades; and (c) means for sparging a fluid into liquid liquid in the reservoir; in which (d) the fluid sparging means and the rotor being so constructed and arranged that the submerged rotor blades and/or the liquid flow they generate disperse the sparged fluid; such that (e) each of the blades is hollow and has a discontinuous leading edge, only a single trailing edge along an acute angle, no external concave surface and an open radially outer end.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an agitator for dispersing a fluid in a liquid.

It is known that a disk-type turbine agitator with a large number of axially aligned flat paddle blades disperses the gas injected as small bubbles into the liquid in the tank and mixes it with the contents of the tank. It is. In use, a low-pressure vortex area is formed behind each rotating blade of the turbine and for gas flow rates often encountered in industry, and the gas tends to collect and form cavities in this area; this is disadvantageous. In particular, it reduces dispersion and mixing efficiency and corrodes turbine blades.

The same problem is found for the dispersion of injected liquids which are less dense than the tank liquid. The inventors have now achieved a turbine agitator that minimizes the generation of turbulence and its deleterious consequences and achieves effective dispersion and mixing.

Accordingly, the present invention comprises a reservoir for a liquid, a rotor disposed within the reservoir and having a number of radially extending vanes, and a device for injecting fluid into the liquid in the reservoir, the fluid ejection device and the rotor, in use. A turbine-type agitator assembly configured and arranged so that one or both of a rotor blade immersed in a liquid and a liquid stream generated by the rotor blade disperses the injected liquid, wherein each blade is hollow and Provided is a turbine-type stirrer assembly, characterized in that it has a single rear end without discontinuous ends, no acute angles, has no concave surface on the outside, and is open at the radially outer end. It is something to do.

In a typical disk-type turbine agitator, the vortex is generated along the surface of the blade in a non-streamlined area;
Separation occurs, for example, at a protruding end (eg, the axial end of a normally axially aligned paddle blade) where the trailing surface is concave or there is no sharp trailing edge.

Any blade meeting the above criteria is suitable for the blade of the present invention. In this, the vanes can have a symmetrical cross-section with a circular, parabolic or oval cross-section smoothly transitioning to a wedge-shaped or sharply elongated parabolic or oval cross-section at the rear end. The term "acute trailing edge" has the meaning of both an angled edge as well as an edge with a sharp radius. A parabolic or elliptical cross-section tip is preferred to improve flow lines around the vane, although the tip portion can be wedge-shaped. The preferred blade shape is a symmetrical airfoil cross section.

The vanes are hollow and have discontinuous tips, for example in the form of holes or in the form of grooves symmetrically provided in the tip surface of the vane, preferably of symmetrical cross-section.

The radially outer ends of the vanes are at least partially open, such vanes having a scooping action and dispersing and mixing the scooped liquid v by feeding it radially outward.

Typical dimensions of the blades of the inventive assembly are: blade length - D/4, protrusion height - D15 (where D is the total length of the rotor diameter).

The blades are usually made of metal or plastic for turbine agitator paddles.

In its general form, the vane has two long axes, a radial and a transverse axis, which define the plane of the vane. The plane of this vane will generally be coincident with or parallel to any plane of rotation described by the vane in use, i.e. the vane will normally be “on” or “with respect to” the rotor axis.
However, the possibility of this angle of attack is not excluded, but the angle is not fixed at the trailing end (or leading end).
may act effectively as an axially projecting end, and/or the rear end portion of the blade surface may act effectively as a concave surface due to its tendency to generate significant vortices. It is easy to understand that it is not that big.

The blades of the turbine rotor can be arranged in the same plane of rotation or in several planes of rotation. Preferably, the vanes are regularly arranged in any one plane to maximize rotational balance. Preferably they are also arranged in accordance with normal engineering practice along the axis such that torsional balance is maximized and for each vane in another plane, for example they have the same number of vanes in each plane. The vanes, and a corresponding number of vanes, are arranged in different planes in axial alignment and regularly staggered relative to each other in the direction of rotation.

The vanes can also be fixed axially to the rotor axis at an angle other than a right angle to generate an axial component of the exhaust flow.

A rotor can have two or more blades.

The mixing efficiency of a turbine generally increases with the number of blades in any plane until the blades approach a lateral dimension such that in use the action of one blade interferes with the action of a subsequent blade. Similarly, the useful number of blade planes is limited by mutual interference between the planes due to their proximity. A further increase in the flow rate does not increase the fluid dispersion efficiency of the turbine as it is further away from a single axial injection source, but rather aids in the dispersion of the liquid and/or liquid-fluid within the reservoir.

In connection with the above, the suitable number of blades is 2 to 24, usually 4 to 12 in the same plane, and the number of planes is 5 to 5, usually 1.

Typically, the dimensions of the rotor are determined by the size of the reservoir, typically its diameter is 1/3 of the lateral dimension of the corresponding reservoir.
Or half.

The fluid ejector can be a single hole or a row, a lattice, a rose, or a ring. The injection fluid is often a gas, although injection of liquid, especially a liquid with a lower density than the liquid in the reservoir, is not excluded.

The rotor and the fluid injection device may be suitably arranged and positioned relative to each other, provided that the fluid is in the volume swept by the rotor blades or in the immediate vicinity of the impingement of the liquid stream generated by the rotor blades (in both cases “ (referred to as "dispersion area").

Although the rotor can be mounted in any position, it is convenient to mount it upright, for example axially away from the injector mounted above or below the reservoir, where the fluid is essentially It is possible to feed the dispersion zone through the liquid under gravity, from below for liquids with a lower density than the gas or liquid in the reservoir, and from above for liquids with a higher density. The injection device is suitably a hole, rose-shaped or ring-shaped relative to the rotor.

The vanes typically do not extend from the rotor shaft itself, as is usual for turbine agitators, but are each attached to an arm or similar structure on the shaft. The axial hole, rose-shaped or ring-shaped injector has a diameter smaller than the diameter of the rotor without overlapping the blades, and the device does not supply fluid to the dispersion zone without a deflector. In such cases, it is convenient to mount the vanes so that they extend from the outer periphery of the rotor disk, with the disk acting as a deflector.

For the above-mentioned normal blade dimensions, if the rotor diameter is D, the disk diameter is usually 3D/4.

The fluid is of course supplied radially outside the volume swept by the vanes, since the liquid delivered to this area by the vanes makes that area a dispersion area; also by using a spray ring. be able to.

Otherwise, the rotor can be mounted transversely to and radially spaced above or below the reservoir-mounted injector and can be essentially gravity fed.

Depending on the rotor configuration, the injectors are suitably axially aligned, transversely straight or arcuate or in the form of a flat or curved grid.

In another embodiment, the injector can be provided in the rotor, for example as a hole(s) in front of each blade or axially remote from the plane of said or one blade.

A suitable or comparable rotor arrangement to the injector and vane arrangement will be obvious to those skilled in the art.

The assemblies of the invention are useful wherever dispersion of two fluid phases is required, but especially in live cell fermentation suspensions or polymer lattices or dispersed materials that degrade or solidify easily. It is particularly useful for low shear thorough mixing for gas-liquid mass transfer processes in sensitive layers.

Hereinafter, the present invention will be explained with reference to the drawings.

In the drawing, the rotor 4 is rotatably mounted vertically in a reservoir 2 (not shown) which holds a liquid 3 (also not shown) in which the rotor 4 is immersed. Rotor 4
is equipped with a shaft 5 (driven by an electric motor 6, not shown), and the shaft 5 has a large number (4 or 6) of radially extending shafts.
vanes 7 are mounted in a single plane by disks or arms 8.

Each vane 7 is of uniform, symmetrical, large cross-section with a single wedge-shaped sharp edge 9 extending in the longitudinal direction of the vane. Each vane 7 is hollow and its distal end surface 10 has a symmetrically disposed all extending in the longitudinal direction of the vane 7. Feather 7
The end 12 of is open. The vanes 7 are mounted so that their central planes of symmetry lie on the same plane.

A device 14 for ejecting gas is mounted in the reservoir below and coaxially with the rotor, as shown in FIGS. 1-3. In FIGS. 1 and 2, a single hole or hole injection ring that does not overlap the vanes 7 is shown. In FIG. 3, the injection ring is below the radially outer area 19 of the volume 18 that the vanes sweep during use. In FIG. 4, the injection device 14 is attached to the hollow shaft 5,
It consists of four perforated tubes projecting from it and communicating with its interior, and extending regularly between and in the same plane as the vanes 6. Those holes 15 are respectively connected to the tube 1
It is located on the rear end surface 16 of 4.

In use, the reservoir 2 is filled with liquid 3 and immerses the blades 7 of the rotor 4, which is rotated in the direction of arrow A. gas 1
7 passes through the jet hole 15 (in Fig. 4, the rotor shaft 5
and through the hollow interior of the rod 13) into the volume 18 or area 19 that the vanes sweep. In all cases the liquid 3 is scooped up into the vane 7 through the groove 11 and discharged through the open vane end 12 into one dispersion area 19 . In FIGS. 1, 2 and 4, gas 17
flows over the outer surface of vane 7 and in all cases the gas passes through area 19
distributed within.

[Brief explanation of drawings]

1, 2, 3 and 4 are schematic illustrations of four embodiments of the invention comprising a rotor and a dispersion device. 4-m-rotor, 5--shaft, 7-blade, 8--111 disk (arm), 9-rear end (of the blade), 10-tip (of the blade), 11-groove. 12--end (of the vane), 13- rod, 1
4- Injection tube.

Claims (1)

[Claims] 1. A liquid storage tank, a rotor provided in the storage tank and having a large number of radially extending blades, and a device for injecting fluid into the liquid in the storage tank, the fluid injection device and the rotor comprising:
A turbine-type agitator assembly constructed and arranged such that, in use, either or both of the rotor blades immersed in the liquid and the liquid stream generated by the rotor blades disperses the injected liquid, the blades each being hollow and discontinuous ends;
characterized by having a single acutely angled rear end, having no external concave surface and being open at the radially outer end;
Turbine stirrer assembly. 2. The turbine-type agitator assembly according to claim 1, wherein each blade has a symmetrical airfoil cross-section that smoothly transitions from a parabolic or elliptical tip cross-section to a wedge-shaped rear end. 3. The turbine type agitator assembly according to claim 2, which has grooves symmetrically provided on the tip surface. 4. The turbine type agitator assembly according to claim 2, wherein the surface of the blade coincides with or is provided parallel to the rotational surface of the blade. 5. The turbine type agitator assembly according to claim 1, wherein the blades are regularly provided within the same rotation plane or within a plurality of parallel rotation planes. 6. The blades are arranged in a number of parallel planes of rotation, each plane of rotation having the same number of blades, and corresponding blades in different planes being aligned in the axial direction or regularly staggered in the direction of rotation in all planes. A turbine type agitator assembly according to claim 5. 7. The turbine type agitator assembly according to claim 5, which has 4 to 12 blades in one rotational plane. 8. The vane is mounted on a horizontal rotating plate and the assembly is arranged such that in use the disc deflects the injected fluid towards the volume swept by the vane. Aggregation. 9. An assembly according to claim 1, wherein the injector is arranged such that, in use, the injector supplies the fluid injected by the injector to an area radially outside the volume swept by the vanes. 10. The assembly according to claim 1, wherein the injection device is attached to the rotor.